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Cell Prolif ; 54(8): e13096, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34240779


OBJECTIVES: PKM1 and PKM2, which are generated from the alternative splicing of PKM gene, play important roles in tumourigenesis and embryonic development as rate-limiting enzymes in glycolytic pathway. However, because of the lack of appropriate techniques, the specific functions of the 2 PKM splicing isoforms have not been clarified endogenously yet. MATERIALS AND METHODS: In this study, we used CRISPR-based base editors to perturbate the endogenous alternative splicing of PKM by introducing mutations into the splicing junction sites in HCT116 cells and zebrafish embryos. Sanger sequencing, agarose gel electrophoresis and targeted deep sequencing assays were utilized for identifying mutation efficiencies and detecting PKM1/2 splicing isoforms. Cell proliferation assays and RNA-seq analysis were performed to describe the effects of perturbation of PKM1/2 splicing in tumour cell growth and zebrafish embryo development. RESULTS: The splicing sites of PKM, a 5' donor site of GT and a 3' acceptor site of AG, were efficiently mutated by cytosine base editor (CBE; BE4max) and adenine base editor (ABE; ABEmax-NG) with guide RNAs (gRNAs) targeting the splicing sites flanking exons 9 and 10 in HCT116 cells and/or zebrafish embryos. The mutations of the 5' donor sites of GT flanking exons 9 or 10 into GC resulted in specific loss of PKM1 or PKM2 expression as well as the increase in PKM2 or PKM1 respectively. Specific loss of PKM1 promoted cell proliferation of HCT116 cells and upregulated the expression of cell cycle regulators related to DNA replication and cell cycle phase transition. In contrast, specific loss of PKM2 suppressed cell growth of HCT116 cells and resulted in growth retardation of zebrafish. Meanwhile, we found that mutation of PKM1/2 splicing sites also perturbated the expression of non-canonical PKM isoforms and produced some novel splicing isoforms. CONCLUSIONS: This work proved that CRISPR-based base editing strategy can be used to disrupt the endogenous alternative splicing of genes of interest to study the function of specific splicing isoforms in vitro and in vivo. It also reminded us to notice some novel or undesirable splicing isoforms by targeting the splicing junction sites using base editors. In sum, we establish a platform to perturbate endogenous RNA splicing for functional investigation or genetic correction of abnormal splicing events in human diseases.

Edição de Genes , Piruvato Quinase/metabolismo , Processamento Alternativo , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Regulação para Baixo , Éxons , Feminino , Células HCT116 , Humanos , Mutagênese , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Piruvato Quinase/genética , Regulação para Cima , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(4): 335-338, 2021 Apr 10.
Artigo em Chinês | MEDLINE | ID: mdl-33834459


OBJECTIVE: To assess the impact of confined placental mosaicism (CPM) on non-invasive prenatal testing (NIPT) and pregnancy outcomes. METHODS: Copy number variation sequencing (CNV-seq) and single nucleotide polymorphism array (SNP-array) were carried out on placental specimen sampled from eight pregnancies with confirmed false-positive NIPT results. The impact of CPM on NIPT and pregnancy outcomes were analyzed based on the laboratory tests and clinical characteristics. RESULTS: Five of the eight cases with false-positive NIPT results were proven to be CPM involving trisomy 9, 13, 21, 22, and X, respectively. The mosaic ratios for different placental regions have varied from 4% to 80%. Two fetuses with confirmed CPM showed fetal growth restriction (FGR) and additional ultrasound abnormalities, 1 fetus showed only FGR. The remaining two fetuses showed normal growth. CONCLUSION: NIPT is highly sensitive to CPM, whilst CPM is an important cause for false-positive NIPT result. CPM may be associated with FGR. Investigation of the presence of CPM is important for both pre- and post-test genetic counseling and management of the pregnancy.

Mosaicismo , Resultado da Gravidez , Variações do Número de Cópias de DNA , Feminino , Humanos , Gravidez , Diagnóstico Pré-Natal , Trissomia
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 36(5): 498-501, 2019 May 10.
Artigo em Chinês | MEDLINE | ID: mdl-31030443


OBJECTIVE: To determine the origin of supernumerary small marker chromosomes (sSMCs) carried by two fetuses. METHODS: Single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) analysis were carried out on cells cultured from the amniotic fluid samples. RESULTS: SNP-array analysis showed both fetuses to be arr[hg19]22q11.1q11.21(16 888 899-18 649 190)×4, with a duplicated 1.7 Mb region (16 888 899-18 649 190) leading to partial tetrasomy of 22q11.1-22q11.21. FISH confirmed that both fetuses were 47,XN,+mar.ish idic(22)(q11.2) (RP11-958H20 ++),which suggested a diagnosis of Cat-eye syndrome (CES). The appearance of abortuses were consistent with the diagnosis of CES. CONCLUSION: Two fetuses with CES were diagnosed by genetic testing. The latter has provided a basis for genetic counseling.

Feto , Diagnóstico Pré-Natal , Aneuploidia , Transtornos Cromossômicos/diagnóstico , Cromossomos Humanos Par 22 , Anormalidades do Olho/diagnóstico , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Gravidez